Regulating system



H. S. BAKER REGULATING SYSTEM March 18 1924. 1,487,504

Filed April 19. 1921 Ih\/entcr- Harry S. Baker;

his Attorney.

Patented Mar. 18, 1924.

. UNITED STATES PATENT OFFICE.

HENRY STEVENSON BAKER, OF NIAGARA FALLS, ONTARIO, OANAOA, ASSIGNOR TO GENERAL EEOTRIC COMPANY, A CORPORATION OF NEW YORK.

BEGULATING SYSTEM.

Application fled April 19,1921. Serial No. 462,788.

To all whom it may concern:

Be it known that I, HENRY STEVENSON BAKER, a subject of the King of Great Britain, and a citizen of the Dominion of 6 Canada, residing at Niagara Falls, On-

tario, have invented certain new and useful Improvements in Regulating Systems, of

which the following is a specificationl My invention relates to regulatin sys- 1 tems and particularly to voltage regu ating systems in which regulators of the vibratory contact type are employed to effect the desired regulation."

In voltage regulating systems in which regulators of the well known Tirrill type are used sparking sometimes occurs at t 0 main. contacts when the regulators are operating in that portion of their range where the main contacts are in engagement 2 a greater proportion of the time. This sparking is due, in part, to the exciter volt age, which is high at this time, and, in part, to the fact that as the exciter magnetic circuit becomes saturated the changes in the exciter voltage occur much more slowly than when the exciter magnetic circuit is unsaturated, thus causing the movement of the contact, controlled by the direct current magnet, to take place at a as much slower rate so that each time the contactsare opened an arc is formed between the contacts. This arcing results in the contacts becoming pitted and dirty, thereby affecting the operation of the regulator.

An object of my invention is to provide an arrangement for preventing this sparking the main contacts of a regulator of the vibratory contact type.

In accordance with my invention I provide an arrangement whereby a quick positive opening and closing of the main contacts of the regulator is obtained at all times thereby preventing any are being formed between the main contacts.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

The accompanyin drawing'is a diagrammatic view of an a ternating current voltnating current circuit 3, and a field winding 4, which is supplied with current from I an exciter 5. 6 represents the shuntfield of the exciter and 7 is a resistance which is connected in series therewith. The resistance 7 is adapted to be cut in and out oi the circuit of enciter field winding 4; by means of a regulator of the type disclosed in the Tirrill Patent No. 726,234. As shown in the drawing, the regulator com prises a direct current lever 8 and an alternating current lever 9, the former being operated by an electromagnet 10 having a core 11 connected to one end of the lever 8. The other end of the lever 8 carries one of the main contacts 12. The coil of the electromagnet 10 is'connected across the en'- citer brushes and a resistance 13 is included in this circuit. The lever 8 is pivoted at it and acts against a spring 15. The alternating current lever 9 is pivoted at 16 and is connected at one end to a core 1.? and at the other end carries the main contact 18 and a counterweight 19. The core I? is adapted to be drawn upwardly a distance depending upon the current flowing through the coil of an electromagnet 20 which is connected across one phase of the alternating current circuit 3 by means of a transformer 21. The main contacts 12 and 18 control a circuit across the exciter terminals which include the winding '22 or the control relay 23. The control relay 23 is also provided with a difierential winding 25 which is permanently connected across the exciter brushes in parallel with the winding 22. A common resistance 2a is included in the circuits of the windings 22 and 25'. The control relay 23 is also provided with an armature 26 which is pivoted at 27 and is connected to one-terminal of the regulatin resistance 7 The armature 26 is ada te to engage a stationary contact 29, w ich is connected to the other terminal of the resistance 7, when both of the windings 22 and 25 are energized thereby completing a short circuit around the resistance 7 When, however, the winding only is energized the relay 23 attracts its armature 26 against the force exerted by a spring 30 thereby opening the short circuit around the resistance 7.

In order to obtain a positive opening and closing of the main contacts at all times, I connect an impedance device, such as a resistance 32, between the main contact 18 and a point between the coil of the electromagnet 10 and the resistance 13 so that the current which flows through the resistance 32 when the main contacts 12 and 18 are in engagement also flows through the resistance 13.

Inasmuch as the operation of voltage regulating systems of the type shown in the drawing is well known in the art, a complete description of the operation is deemed unnecessary. It will be observed that every time the main contacts 12 and 18 are in engagement a circuit is completed in parallel to the winding of the electromagnet 10 through the resistance 32 and the contacts 12 and 18.- When the main contacts 12 and 18 move out of engagement with each other this circuit through the resistance 32 is opened. Consequently, every time the contacts separate the amount of current flowing through the resistance 13 decreases thereby decreasing the voltage drop across this resistance and increasing the voltage impressed across the coil of the electromagnet 10 so that the current through the coil increases. This current change occurs very auickly so that the core 11 is given a quick ownward movement thereby assuring a quick positive opening of the contacts which prevents an are from being formed between the contacts. Since this quick opening of the contacts occurs each time they are moved out of engagement with each other arcing at the contacts is entirely eliminated. When the contacts 12 and 18 engage, a similar action takes place whereby a quick positive closing of the contacts is assured. As soon as the contacts engage the circuit through the resistance 32 in parallel to the coil of the electromagnet 10 is completed. Consequently, the current through the resistance 13 increases thereby increasing the voltage drop across the resistance 13 and decreasing the voltage across the coil of the electromagnet 10. The pull exerted by the electromagnet 10 is therefore decreased so that the spring 15 moves the contact 12 into positive engagement with the contact 18. The resistance 32 is preferably made .of such a value that onl a very small change in voltage impressed across the terminals of the coil of the electromagnet 10 is produced by the opening and closing of the main contacts so that the electromagnet 10 may operate in'the usual manner to prevent hunting.

The opening and closing of the main contacts 12 and 18 control, in the well known manner, the operation of the control relay 23 which in turn controls the short circuit around the resistance 7 to maintain the volta e of the generator 1 at a predetermine value.

While I have shown and described one embodiment of my invention various modifications and changes ma be made therein without departing from t e spirit and scope of my invention and I aim to cover in the appended claims all such modifications and changes. i

What I claim as new and desire to secure by Letters Patent of the United States, is

1. In a regulating system, the combination of a pair of cooperating contacts arranged to effect by their engagement and disengagement the desired regulation, means for actuating one of said contacts in accordance with the condition being regulated, an electromagnet for operatm the other one of said contacts, a source 0% current connected to said electromagnet, an impedance device in the circuit of said electromagnet and a second impedance device arranged to be connected in parallel to the coil of said electromagnet by the engagement of said contacts.

2. In a regulating system, the combination of a pair of cooperating contacts, an electromagnet operated in accordance with the condition being regulated for actuating one of said contacts, a second electromagnet for actuating the other contact, a source of current connected to said second electromagnet, an impedance device in the circuit of said second electromagnet, a control relay, a circuit for said control relay arranged to be connected to said source by the enga ement of said contacts, and a second impe ance device connected between one of said contacts and one terminal of said second electromagnet so that said second impedance device is connected in parallel to the coil of said secondelectromagnet when said contacts are in engagement.

3. In a regulating system, the combination of a pair of cooperating contacts arranged to effect by their engagement and disengagement the desired regulation, means for actuating one of said contacts in accordance with the condition being regulated, an electromagnet for operating the other one of said contacts; a source of current connected to said electromagnet, an impedance device in the circuit of said electromagnet, and means for varying the voltage drop 'across said impedance device to produce a quick opening and closing of said contacts.

4. In a regulating system, the combination of a pair of cooperating contacts arranged to effect by their engagement and eme 3 disengagement the desired regulation, electromegnst, and means for completing means or actuating one. of said contacts a circuit in pamiiei with snid electromagnet in accordance with the condition being rcgand in series with said impedance device W ulated, an electromagnet for operating the when said contacts are in engagement.

1 other one of said contacts, a source of can In witness whereof, I have hereunto set rent connected to said electromagnet, on my hand this fourteenth do of April 1921. impedance device in the circuit of ssid HENRY STEVEN ON BAKER. 

